I used a clam-shell type for years before switching to the LPKF. The ZelPrint LT300 looks a lot like the LPKF one. I prefer the LPKF or ZelPrint style because they are capable of getting better (more accurate and more consistent) prints when compared to a clam-shell type manual printer. Manncorp appears to only carry the clam-shell type.

If you look carefully at the photo of the ZelPrint you will see the PCB on the left hand side. The PCB has a thin film of polycarbonate pulled across it for alignment. The PCB (and polycarb) is slid to the right under the stencil and then lifted up to the stencil. The stencil does not move. After you squeegee the paste onto the board (covered with the polycarb) you lower and move the board left, back to the starting position. Now you can do a good alignment of the board by using the left-right, up-down, and rotation knobs. Because the paste is on the polycarbonate, and you are adjusting the PCB under it, you can see the alignment much better than trying to look through the stencil at the board.

The LPKF will hold a stencil mounted in a 12X17 cast frame nicely. Both the LPKF and the ZelPrint allow you to load a frameless stencil into their frame, but that can be a little time consuming. The advantage to using frameless stencils is that framed stencils take up a lot of room.

It looks like the Zelprint LT300 is LPKF too... The first one was an LPKF Protoprint S, and the second was an LPKF Zelprint LT300. Are there any of these printers that have a device to actually apply the solder paste with consistent and constant pressure?

Does any framed stencil work with it? Like ones from Stencils Unlimited?

I use the LPKF model S. Operator uses a urethane(?) squeegee. Pressure and speed are controlled by the operator, which hasn't been a problem for me. The only problem I had was that I would forget to raise the PCB before I would start to squeegee the paste, and this was only because I used a clam-shell printer for years.

Not any framed stencil will just drop in place. I had a few very old 12x12 framed stencils that I had to build an adapter to use. All models of 12x17 cast Aluminum frames from Fineline Stencils (FCT) have fit well though. LPKF provides a Gerber file for the stencil mfg so that your stencil can be built to fit their removable frame.

"Have you considered a refurbished SMTech Benchmark printer from SigmaPrint?" I tried that. The reply I received stated that they hadn't had any for years (despite showing them as available on the site). They are apparently not a good bet because the uC they use is no longer available and if it fails, you bin the machine.

When did you receive the reply "that they hadn't had any for years"? I would be interested to hear who sent you this.

I'm a founder director of Sigmaprint and previously a employee of both SMTech and Speedline Technologies. I can currently see 3 Benchmark printers on our shop floor. One of them along with a UP100MV is currently undergoing a refurbishment for a customer in the new year!

You are partially correct in saying that they use a now obsolete micro-controller, knowing this however we still have a stock of just under 500 of them (currently using them at a rate of 10-20 a year. Taking this in mind at worst rate you may have to bin the machine 2035.